Developmental Coordination Disorder (DCD) as a Distinct Syndrome: A Conceptual and Empirical Investigation Judith Mary Peters A thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology Institute of Education University of London 2006 Abstract Bright children who have abnormal difficulty in acquiring age-appropriate motor skills are of increasing concern to parents, teachers and health professionals. Longitudinal studies have found the condition to be associated with educational under-achievement, impaired social development and disturbed mental well-being in adult life. Now officially known as Developmental Coordination Disorder (DC D), the question of whether this condition should really be viewed as a distinct diagnostic entity is the central theme of this thesis. In the opening chapters, the history of terms used to signify 'clumsiness' of movement is reviewed and the different implications of treating such behaviour as a symptom or syndrome is considered. Discussion then moves to the overlap between DCD and other childhood conditions and the question of how these should be conceptualised. Five studies comprising the empirical component of the thesis employed a variety of methodologies. Two questionnaire-based studies showed that in this area, neither consensus on terms nor equitable service provision has yet been achieved. A third, retrospective study, searched for evidence of sub-types within a large sample of DCD children, successfully replicating some of the cluster groups reported by others. In a final, prospective study, a two-stage identification process was followed by 'blind' assessment of boys with DCD, Asperger Syndrome or Joint Hyper-mobility Syndrome. Novel to this area was the inclusion of experimental measures, including dual-task performance, in which motor and cognitive tasks were combined. The results showed that although the group with AS were significantly poorer on ball skills than those with OCD, the general nature of motor difficulties was not systematically constrained by diagnosis. Together, these studies support the thesis that DCD exists as a separable syndrome, but bear less decisively on the existence of subtypes. A series of real-life case studies illustrates the problems associated with differential diagnosis and the implications for appropriate intervention. 2 Declaration and Word Count All the empirical studies reported in this thesis were planned, executed and analysed by the candidate. Co-authors in Studies One and Two participated in the discussion results and commented on the write up of papers for publication. The candidate also confirms that the work submitted is her own and that appropriate credit has been given where reference has been made to the work of others. Word count: 94951 words 3 Acknowledgements This research was supervised by Sheila Henderson. I am deeply grateful to her for her time, energy, perfectionist demands, patient supervision and positive encouragement throughout. I am grateful to the Physiotherapy Department at GOSH who accommodated the outpatient assessments, and staff who gave support and encouragement (Head of Department, Devala Dookun; Acting Head, Rosa Schmale). I thank Beverleigh Christian, Nathan Hasson, Betty Hutchon, Alice Jones, Sue Maillard, and Angela Webb for referrals to the final research study and am particularly indebted to Rebecca Worsley and Monica Murray for co-ordinating the initial referrals and administering the vocabulary test, assisted by Debbie Jackson. Many others have provided advice for this work. In particular the following deserve thanks: Peter Hill for initial fruitful discussions of the project, provision of assessment tools and links to referral sources; Charlie Owen for patient advice on statistics; Eric Hadley for constructing the peg board for Study 5; Monica Booth and Gwen Dornan for assessing handwriting samples; Dan Shaw for attending to frequent computer idiosyncrasies; Kate Sym for assistance with formatting the final manuscript; Ellen Cotter for her assistance, Leslie Henderson for his perspicacious comments and Cordon Bleu expertise. I am grateful to Lucy Alderson, Anna Barnett, Melanie Bladen, Eleanor Main, Liz Stephenson and many others for helpful discussions, friendship, support and encouragement. I acknowledge the help of schools who referred children but above all I am indebted to all the parents and children who took part in the research. From them I learnt much about the real impact of movement competence in every day life. Finally, I thank my children, Carolyne, Sarah and Christopher for their moral support and encouragement throughout an exciting and challenging journey. Huge thanks also go to my husband, Timothy who tolerated my absorption in this research and who read many drafts of the manuscript with a critical eye, and provided essential support at the times when it mattered most. 4 List of Abbreviations ADD/ADHD Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder AHP Allied Health Professional AS Asperger Syndrome ASD Autism Spectrum Disorder ASSQ High Functioning Autism Spectrum Screening Questionnaire BJHS Benign Joint Hypermobility Syndrome BPVS British Picture Vocabulary Scales CD Conduct Disorder CP Cerebral Palsy DAMP Disorders of Attention, Motor Control and Perception DCD Developmental Coordination Disorder DMD Duchenne Muscular Dystrophy DSM Diagnostic and Statistical Manual FTND Full Term Normal Delivery GOSH Great Ormond Street Childrens' Hospital HFA High Function Autism ICD International Classification of Diseases LSCS Lower Section Caesarean Section M-ABC Movement Assessment Battery for Children MBD Minimal Brain Dysfunction MD-hyp Motor difficulty plus hypermobility MD-nonhyp Motor difficulty without hypermobility NFl Neurofibromatosis Type I NVLD Non Verbal Learning Disability OCD Obsessive Compulsive Disorder ODD Oppositional Defiant Disorder OED Oxford English Dictionary OT Occupational Therapist/therapy PDD Pervasive Developmental Disorder PDD-NOS Pervasive Developmental Disorder Not Otherwise Specified PIQ Performance IQ PT Physiotherapist/therapy RD Reading Disorder SALT Speech and Language Therapist SDD-MF Specific Developmental Disorder of Motor Function SDQ Strengths and Difficulties Questionnaire SENCO Special Education Needs Coordinator SIPT Sensory Integration and Praxis Tests SLI Specific Language Impairment TD Typically Developing TS Tourette Syndrome VIQ VerbalIQ VMI Developmental Test of Visual Motor Integration V-P Verbal-Performance WISC Wechsler Intelligence Scale for Children 5 Contents Abstract ....................................................................................................................... 2 Acknowledgements ..................................................................................................... 4 List of Abbreviations ................................................................................................. 5 Chapter 1: "Clumsiness" of Movement: A Historical Review ............................. 13 1.0 Introduction ................................................................................................... 13 1.1 Motor dysfunction .......................................................................................... 14 1.2 Terminology: sources of confusion ............................................................... 16 1.3 The use ofa lay term as a label for a "medical" condition .......................... 16 1.4 Dyspraxia and its variants: Terms derived from adult neurology applied to developmental childhood conditions ................................................................... 25 1.5 Terms used to denote a continuum of brain damage - MBD (Minimal Brain Damage) .............................................................................................................. 32 1.6 Geographical and professional individuality ................................................ 36 1.7 Present day .................................................................................................... 37 1.8 Conclusion ..................................................................................................... 42 Chapter 2: Clumsiness as 'Symptom' or 'Syndrome' .......................................... 44 2.0 Introduction ................................................................................................... 44 2.1 Definitions ofsymptom, sign, syndrome, disorder, disease, type, subtype .... 44 2.2 Clumsiness as a symptom or syndrome- the clients' perspective .................. 48 2.3 Clumsiness as a 'symptom' or 'syndrome' - diagnostic issues .................... 51 2.4 Conclusion ..................................................................................................... 76 Chapter 3: Syndrome or Syndromes: DCD Plus or What? ................................. 78 3.0 Introduction ................................................................................................... 78 3.1 Concepts and definitions ............................................................................... 79 3.2 Co-occurring, co-existing, co-morbid from the client's perspective .... ......... 82 3.3 Co-occurring, co-existing - the practitioner's role ...................................... 83 3.4 Developmental disorders - the status quo: separate entries in DSM and ICD ............................................................................................................................. 86 3.5 The literature on co-morbidity,